Field of the Invention
This invention relates to a process for producing (-)-3a,6,6,9a-tetramethyl-dodecahydronaphtho[2,1-b]furan (hereinafter "L-ambrox") represented by Formula (1); ##STR1## which is an important perfumery substance having an excellent aroma of an amber. More particularly, this invention relates to a process for producing the L-ambrox by the use of a (-)-2,5,5,8a-tetramethyl-1-(carboxymethyl)-2-hydroxydecalin (hereinafter "(-)HC acid") represented by Formula (10a): ##STR2## as a starting material, at a low cost and in an industrial scale. This invention also relates to a process for optically resolving (.+-.)-2,5,5,8a-tetramethyl-1-(carboxymethyl)-2-hydroxydecalin, which is a mixture of equal quantities of (-)HC acid and (+)-2,5,5,8a-tetramethyl-1-(carboxymethyl)-2-hydroxydecalin (hereinafter "(+)HC acid"), into (-)HC acid and (+)HC acid to thereby obtain the optically active (-)HC acid or (+)HC acid represented by Formula (10b): which is useful as a starting material for synthesizing a compound having a trimethyl-transdecalin skeleton represented by Formula (A): ##STR3## having a physiological activity or a characteristic aroma, as exemplified by the L-ambrox or the like.